In pursuit of recent studies carried out in our Laboratory on the carboxylation of alkanes to carboxylic acids in systems containing trifluoroacetic acid (TFA) as solvent, and various V and Re compounds as catalysts,[1,2] we have been searching for new more efficient methods to perform such a type of alkane transformations, aiming at the replacement of the considerably expensive, consumable in the reaction and corrosive TFA by another solvent or solvent composition, which could overcome the abovementioned drawbacks. Taking into consideration that the metal-catalysed peroxidative oxidation (namely with H2O2) of cycloalkanes to the corresponding alcohols and ketones can occur in water/acetonitrile liquid medium, as shown by other studies on alkane transformations performed e.g. in our Laboratory,[3,4] we have now found, for the first time, that this mixture of solvents can be also notably suitable for the efficient carboxylation by CO of both gaseous and liquid Cn alkanes to give selectively carboxylic acids having (n+1) carbon atoms even in the absence of a metal catalyst.
The present work has been developed at the Centro de Química Estrutural, Complexo I, Instituto Superior Técnico, Universidade Técnica de Lisboa, within the Ph.D. courses of Dr. M. V. Kirillova and Dr. A. M. Kirillov, as part of projects under the responsibility of Professor A. J. L Pombeiro, supported by the POCI-2010 programme (FEDER funded) of the Foundation for Science and Technology (FCT), and the European network (Human Resources and Mobility Marie-Curie Research Training Network, AQUACHEM project).